Note that RSA 1024 is getting pretty weak (see keylength.com. I would not protect too much important data with it, please try and upgrade to higher keysizes or ECIES if you want faster asymmetric performance during decryption.
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Maarten BodewesAug 25 '12 at 23:09

so 0.002 second take an RSA 1024 decryption with pentium 4 right pooya ?
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marioAug 21 '12 at 20:15

2

@mario: Yes. Order of magnitude for RSA-1024 private-key operations (either decryption, or signature generation) on a Pentium 4 is 1000/second. This will vary tremendously depending on implementation (some are 10 times slower, or 100..), use of CRT (not using CRT slows down by a factor over 3), and use of countermeasures against timing attacks and other side channels. Public-key operations (encryption or signature verification) may be like 50 times faster.
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fgrieuAug 21 '12 at 21:32